* Add support for class private methods
This commit adds parser support for the TC39 Stage 2 Private Methods
proposal.
This commit also changes "key" in ClassPrivateProperty from an
Identifier to a PrivateName, as well as disallowing #constructor as a
valid private field name.
* Add tests for string literal get/set/async
These should be treated as regular methods and not special get/set/async
behaviour.
* Add tests for class private methods
This also removes a test from the Test262 whitelist that failed before
the changes for private methods support and now passes.
* Modify class private prop tests for PrivateName
* Add class private prop tests for #constructor
* Fix existing ASI test case failure
* Test runner: Detect extra property in 'actual' but not in 'expected'.
Also update all expected.json where this would result in errors.
* Include rmExpected.js script in case it is needed again
* Increase test coverage
* Test for error when binding `this` in destructuring pattern
* Ignore coverage of inAsync check in parseAwait - already checked externally
* Ignore coverage of default case in checkPropClash
* Remove unused parameter isAsync from parseParenAndDistinguishExpression
* Ignore coverage of an `else` branch in flowParseTypeParameterDeclaration
* Flow: remove unused parameters to flowParseTypeAnnotatableIdentifier
* Flow: ignore coverage of pass-through throw statement in parseConditional
* Flow: Add test for error on property with type param
* Flow: ignore coverage of pass-through throw statements in parseMaybeAssign, parseArrow
* Add test for error on XML-style comment in module code
* Update test for error on method in object pattern
* Test for error: "Only '=' operator can be used for specifying default value"
